California Department of Transportation
 

Road Information - Winter Driving Tips - Chain Controls

Before driving, check with the Caltrans Highway Information Network (CHIN) 800.427.7623

Types of Chain Controls:

During the winter months, motorists may encounter traction chain controls in the mountain areas within California. When chain controls are established, signs will be posted along the road indicating the type of requirement. There are three requirements in California.

Requirement 1 (R-1): Chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 pounds gross weight and equipped with snow tires on at least two drive wheels. Chains must be carried by vehicles using snow tires. All vehicles towing trailers must have chains on one drive axle. Trailers with brakes must have chains on at least one axle.

Requirement 2 (R-2): Chains are required on all vehicles except four-wheel-drive vehicles under 6,500 pounds gross weight and equipped with snow tires on all four wheels. Chains for one set of drive wheels must be carried by four wheel-drive vehicles using snow tires.

Requirement 3 (R-3): Chains are required on all vehicles without exception.

R-1 and R-2 are the most common conditions. A highway will often be closed before an R-3 condition is imposed. Some local areas may use variations of these designations. You must follow the directions on the signs posted for chain controls or any instructions given by Caltrans or CHP personnel at chain control check points, even if these are at variance with broadcast road condition reports or information contained herein.

Snow-tread Tires:

The California vehicle code section 558 defines a snow-tread tire as follows, " A 'Snow-tread tire' is a tire which has a relatively deep and aggressive tread pattern compared with conventional passenger tread pattern". Snow-tread tires can be identified by examining the sidewall of the tire where the letters MS, M/S, M+S or the words MUD AND SNOW have been stamped into the sidewall.

Tire Traction Devices:

The California vehicle code section 605 defines tire traction devices as follows: " Tire Traction Devices are devices or mechanisms having a composition and design capable of improving vehicle traction, braking and cornering ability upon snow or ice-covered surfaces. Tire traction devices shall be constructed and assembled to provide sufficient structural integrity and to prevent accidental detachment from vehicles. Tire traction devices shall, at the time of manufacture or final assembly, bear a permanent impression indicating the name, initials or trademark of the assembling company or primary manufacturer, and the country in which the devices were manufactured or assembled in final form."

If you would like to view a full version of the California Vehicle Code it can be located at the following location, under California Law: http//www.leginfo.ca.gov

The Department of Transportation does not sell nor recommend specific brands of tire chains. It is best to check your vehicle manufacturer's specifications for use of tire chains/traction devices.

A chart depicting the proper placement of traction devices is available in Adobe Portable Document format. You can easily print this file for your records. When printing the file use the printer button in the Acrobat Reader not the printer button from your browser. If you do not have the most current version of Acrobat Reader from Adobe click here to download.